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A zero-energy building is one with zero net energy consumption – meaning the total amount of energy used by the building on an annual basis should be covered to a very significant extent by renewable energy created onsite or nearby.

The definition of Nearly Zero Energy Buildings as defined in Directive 2010/31/EU on the energy performance of buildings (recast) is:“Nearly zero-energy building’ means a building that has a very high energy performance, as determined in accordance with Annex I. The nearly zero or very low amount of energy required should be covered to a very significant extent by energy from renewable sources, including energy from renewable sources produced on-site or nearby;”

All buildings completed after the 31st of December 2020 must achieve the nZEB standard.

The nZEB Standard

After January 1st 2021, unless a building meets the nZEB standard, a certificate of compliance with Building Regulations cannot be signed off and a building cannot be occupied. It is therefore extremely important that those involved in the construction industry are aware of their responsibilities and capable of providing buildings that meet the standard. This will likely require companies, both large and small, to inform on the requirements for nZEB compliance.

Under the standard, a typical dwelling will be required to have a heating load of no more than 45Wh/m2 per year with a significant proportion of this energy to be produced by renewable energy sources produced on-site or nearby. In terms of BER certificates, this will have the effect that all new dwellings should be rated A3 or higher.

Achieving nZEB

In order to achieve nZEB, a number of strategies can be implemented, including:Use of efficient lighting High levels of insulationImprovements in airtightnessConsideration of glazing ratios Improvements in glazing insulation valuesEnhanced calculation of linear thermal bridging Use of renewable energy to provide a substantial part of the energyCompliance to the standard needs to be demonstrated and it will be necessary for design teams to develop an understanding of the software used to do this.

Greater coordination between design team members will be required from the outset to achieve an integrated, nZEB compliant design, with Mechanical and Electrical Engineers instrumental in achieving the standard through efficient lighting, M&E services and renewables. At J.V. Tierney & Co. we can provide design advice in the design of nZEB compliant buildings. If you have a building project that is due for completion after December 31st 2020, give us a call on + 353 1 421 4900 for advice on achieving the nZEB standard.